The present invention relates in general to optical fiber light transmission systems, and in particular to connectors for use in coupling optical fiber conductors together.
Prior art fiber optic cable connectors have been provided for joining cables which contain optical fibers. The cables are coupled so that the end faces of terminal ends of the optical fibers of different cables are aligned along respective mating planes for transmitting light signals between mated optical fibers. Such fiber optic connectors have been provided for single channel, multi-channel, single mode and multi-mode cables. The terminal ends of the optical fibers contained in such cables are typically included within termini, which include ferrules that extend over the terminal ends of cores of the optical fibers. The terminal ends of the optical fibers pass through the ferrules, with the terminal end faces of the optical fibers fitting flush with terminal ends of the ferrules. When two of the cables are coupled together, opposing ferrules are mated together in an abutting arrangement, with the terminal end faces of the optical fibers coaxially aligned along a mating plane for transmitting light signals therebetween. The alignment between two of the mating ferrules is critical in order to eliminate transmission losses which occur due to diffusion and reflection of the light being transmitted between mated optical fibers.
In some applications, adjacent optical fibers have been coupled using expanded beam-type termini connection, in which the light signals from one of the optical fibers is expanded, or spread apart, and then collimated upon exiting a terminal end of a first one of the mating termini. The collimated light signals are then received by a second one of the termini that focuses the light into a single one of the optical fibers. The termini of adjacent ones of the optical fibers have been coupled utilizing split sleeves. The split sleeves are split along one side by a slot that runs the full longitudinal length of respective ones of the sleeves, typically parallel to the longitudinal length of the optical fibers so that the sleeves act like a resilient, spring-like member to clamp down on the exterior of the termini to align the two mating optical fibers. The two mating termini are usually gimbaled such that the terminal ends of the termini are free to angularly move along arcuate paths which extend transversely to the longitudinal length of the sleeve. This allows the terminal ends of respective ones of the termini, that is, the axes of the termini, and the optical fibers, to be coaxially aligned when being fitted within the split sleeves. In some prior art connectors, O-ring seals have been used to both seal against respective ones of the termini, and also to provide gimbal surfaces for allowing annular alignment of the axes of the termini being mated.
In some fiber optic cabling applications, connectors are selected such that certain types of connectors will not intermate with other types of connectors, such as to prevent the connection of particular devices to one another. Connectors of different size and configuration are usually provided by components which cannot be intermixed should one component be in short supply and another component be readily available. Additionally, some fiber optic applications have bulkhead mounting connectors, such as receptacles, for intermating with connectors mounted to cable ends. One convenient method of making sure particular cable connections are not crossed at opposite ends of the cables from the panels, or to provide connectors which are of various sizes and configurations such that non-compatible connectors cannot be intermated. This typically requires stocking of different types of connector halves.
A multi-channel fiber optic connector is provided having a plug connector half and a receptacle connector half. The plug and the receptacle have respective inserts that include exterior peripheries of a particular shape for mating with an interior profile of a housing of the receptacle. The peripheries of the inserts are preferably defined by cylindrical bodies having respective tabs which protrude outward from the outer diameters of the inserts. The interior profile of the receptacle housing defines a recess for receiving the tabs to both angularly align the insert associated with the receptacle and to angularly align the insert associated with the plug. The recess in the receptacle housing is defined by a groove which extends parallel to the longitudinal length of the receptacle housing, with the same groove receiving the protuberant tabs of both inserts to angularly align the inserts. The inserts have fiber optic termini mounted therein. The insert associated with the plug is comprised of a main insert body and an insert cap, with the termini of the respective insert being mounted to the main insert body and alignment sleeves for aligning mating termini being retained in the insert cap. The insert cap includes the tab for fitting in the groove of the receptacle housing, such that the plug may be modified for mating with an alternative receptacle by replacing the insert cap with a corresponding insert having a protuberant tab which is alternatively sized and shaped for fitting in the corresponding groove of the alternative receptacle.